Studio Monitor Tweeters are Buzzing Loudly out of Nowhere

[Swamp Ape]

I have a set of Samson Resolve 50a's running through an Alesis i04. Same setup for years now, but on Friday my tweeters started buzzing so loudly that they have become unusable.

This happens even when there is no patch cord hooked up, and happens in every room in my house, even when not hooked up to anything. Also, other sets of speakers all still work fine through the i04. I thought it was a ground loop issue, or a failing patch cord, or maybe my interface, but it has to be the monitors.

Anybody seen this before? Why would they both go out at the same time?

[Softsynth]

Both of them have the same fault?

[Swamp Ape]

Yeah, it happened at the same time to both of them while I was out. I came back and they were buzzing so loud I could hear them across the house.

[Softsynth]

Weird, they both have separate amplifiers per speaker (if I am looking at the right product pictures).
Any possible evidence of any nasty power cuts during this time?

[Swamp Ape]

Yeah, they are separately powered.

I wondered if maybe a power cut or surge affected them but I didn't really see any evidence - the clocks were all still correct for example. I was gone all day though, so I can't say for sure.

[hopi]

well that'll teach you to go out and leave your monitors on their own!

very odd and very unlikely, but not impossible, that the same capacitor [or whatever] would fail in them both at the same time

but .... not impossible.....

have you taken them to some other location than your house to see if they do it there?

[Swamp Ape]

Yeah, same results in several rooms and even the porch.

[hopi]

well more than likely that covers it BUT I was thinking about trying them at some other house... just to eliminate the odd chance that it is something coming into your house circut that only the electronics in those speaker are sensitive to...

admittedly it is a rare possibility

[Swamp Ape]

I might ask the neighbors when they are home. I guess today I will take them apart and see if a capacitor went bad simultaneously in both of them somehow.

[Swamp Ape]

Well, the capacitors don't look blown but I can't check them because my multimeter is suddenly missing.

I'm going to order some new ones and cross my fingers that replacements will fix them.

[karbomusic]

Originally Posted by Swamp Ape

Well, the capacitors don't look blown but I can't check them because my multimeter is suddenly missing.

I'm going to order some new ones and cross my fingers that replacements will fix them.

Bad caps don't have to look bad. I've fixed two pieces of gear with bad caps in the last 6 months (guitar amp/Fireface 800) and the caps looked perfectly fine for both.

That doesn't mean that's the problem but if filtering caps, +1 that they 'could' have failed in such a way that they are no longer filtering ripple. As far as at the same time, I suppose that's possible too on an assembly line with two caps coming out of the same lot probably manufactured within seconds of each other and electrolytic caps are typically not if, but when, even if just sitting there not being used (albeit heat doesn't' help either).

[Swamp Ape]

Yeah, the weirdest part is that they both failed at the same time, or at least in the same day. These monitors do put out a bit of heat, though, so maybe I should get out of the habit of leaving them on sometimes.

....if I can fix them.

[Swamp Ape]

Well, changing the caps did nothing. Still buzzing. Anybody else got any ideas? I'm about to give up and start looking for new ones.

[Geoff Waddington]

Do you have any signal coming out of the tweeters at all ?

If not, it might be that they got a nasty input while you were out (RFI, whatever) that sent them into oscillation (or some other instabilty, out-of-opeartion-reange-condition, etc.) that blew both tweeter amps, and now they just hum, you only hear signal from the low end amps and woofers.

[Swamp Ape]

No, I still get sound through the tweeters, just buried behind all the buzz.

[karbomusic]

Originally Posted by Swamp Ape

No, I still get sound through the tweeters, just buried behind all the buzz.

Just noticed you are in Asheville, I'm in Charlotte. I was just in Asheville back in October. Anyway, so you can still hear music through these? That does sound like a PSU filter cap, but you changed them. And you said they do this with nothing plugged into them at all, on patch cord, nothing? I'm about stumped, I assume you observed proper polarity with the caps, I'm grabbing at straws.

[Swamp Ape]

Yeah, I double checked the polarity just in case, made notes for myself. I too am completely stumped at this point.

Thanks for the advice everyone.

[Arran]

Can you take one to a completely different location, miles away? I'm thinking maybe something rf borne that's peculiar to your location like a new WiFi or mobile phone installation.

[bolgwrad]

Ferrofluid tweeters? May explain why both went together, but not necessarily the buzz.

http://emotivalounge.proboards.com/t...fluid-tweeters

[Swamp Ape]

Originally Posted by Arran

Can you take one to a completely different location, miles away? I'm thinking maybe something rf borne that's peculiar to your location like a new WiFi or mobile phone installation.

Potentially, but not anytime this weekend. Any way to shield against this kind of thing? Cables are already shielded.

[Swamp Ape]

Originally Posted by bolgwrad

Ferrofluid tweeters? May explain why both went together, but not necessarily the buzz.

http://emotivalounge.proboards.com/t...fluid-tweeters

Never heard of this. I might have to take a tweeter apart and look, but this doesn't sound like quite the problem.

Interesting though.

[hopi]

any chance of simply replacing the tweeters?

next question ...just to be sure... if you disconnect the tweeter, does the noise really go away?

[Punk Duck]

Hi.

Can I suggest that you should try a bit more elimination of the cause and source of the buzz.

Have you tried removing a tweeter and connecting it to another amplifier (carefully!) to see if it still does it.

And conversely, connect another tweeter or old headphone driver, whatever in a tweeters place.

Then you'll know if its the amplifier or the tweeter.

I've found that just replacing parts and hoping for the best is a sure way to waste money and probably mess something else up in the process!

Good luck.

PD

[Swamp Ape]

Originally Posted by hopi

any chance of simply replacing the tweeters?

next question ...just to be sure... if you disconnect the tweeter, does the noise really go away?

I am debating replacing the tweeters, if I can find parts that match. The noise does indeed go away when the tweeters are disconnected, at least as far as I can tell. I thought it might be 60 hz hum, but the woofers are rated down to 20 hz and I can't hear any noise through them alone.

[Swamp Ape]

Originally Posted by Punk Duck

Have you tried removing a tweeter and connecting it to another amplifier (carefully!) to see if it still does it.

And conversely, connect another tweeter or old headphone driver, whatever in a tweeters place.

Then you'll know if its the amplifier or the tweeter.

I've found that just replacing parts and hoping for the best is a sure way to waste money and probably mess something else up in the process!

This might be the next step, although I won't have any time this weekend to mess around with this stuff. I definitely hear you on that last part though.

[hopi]

just to toss in another possible source of the problem... there must be a crossover board... yes?

so if the tweeters on their own are ok, that would be the next place to look